/Engine/Source/Editor/GraphEditor/Public/GraphDiffControl.h
Looks through the supplied graph for a node that best matches the one specified. Sometimes (when diffing separate assets) there could be more than one possible match, so providing a list of already matched nodes helps us narrow it down (and prevents us from matching one node with multiple others).
A pair of nodes (including the supplied one) that best match each other (one may be nullptr if no match was found).
static [FNodeMatch](API\Editor\GraphEditor\FGraphDiffControl\FNodeMatch) FindNodeMatch ( [UEdGraph](API\Runtime\Engine\EdGraph\UEdGraph) * OldGraph, [UEdGraphNode](API\Runtime\Engine\EdGraph\UEdGraphNode) * NewNode, [TArray](API\Runtime\Core\Containers\TArray)< [FNodeMatch](API\Editor\GraphEditor\FGraphDiffControl\FNodeMatch) > const & PriorMatches )